Plug for electrical apparatus



Jan. 3, 1956 v. KOBLER ETAL PLUG FOR ELECTRICAL APPARATUS Filed Sept.20, 1954 IN VE N TORS United States Patent PLUG FOR ELECTRICAL APPARATUSVictor Kobler and Werner Kobler, Zurich, Switzerland ApplicationSeptember 20, 1954, Serial No. 456,899

Claims priority, application Switzerland September 29, 1953 3 Claims.(Cl. 339-36) The present invention relates to plugs for electricalapparatus, and more particularly to such plugs, which are provided witha protection cap for sensitive parts of the apparatus.

Such plugs often have the disadvantage, that due to the protection cap,which usually is fixed within the range of the plug contacts, they maynot be inserted into the corresponding sockets. This disadvantage occursnot only with plugs having pins, which are to be inserted into thebushings of countersunk sockets, but particularly with plugs havingso-called bayonet armatures, as they are common in certain countries.

The present invention has as its object the provision of a plug, withwhich the disadvantage mentioned is avoided.

According to the invention the plug is characterized in that theprotection cap and the insulating body of the plug, having at its oneend the plug contacts, form two separate parts, a support being slidableon the insulating body and on the current supply cable leaving thelatter.

By displacing the support of the protection cap on the insulating bodyit is possible to provide for the distance between these contacts andthe protection cap, which is necessary for the proper insertion of thecontacts into the corresponding socket.

If necessary the protection cap with its support can he slid backcompletely onto the current supply cable,-

which is led into the insulating body at the end thereof facing awayfrom the plug contacts.

The accompanying drawing shows two embodiments of the plug according tothe invention.

Figs. 1 and 2 show perspectively the first embodiment, the protectioncap being in its position of use and its out of-use positionrespectively.

Figs. 3 and 4 the second embodiment in analogous positions to Figs. 1and 2, and

Fig. 5 the insulating body of the second embodiment with a fragmentaryaxial section.

The plug shown in Figs. 1 and 2 has an insulating body 1, carrying in aknown manner the plug pins 2 as well as a protection cap 3 being formedas a separate part, which in the present case serves for the protectionof the cutter-head of an electrical dry-shaver. The protection cap,being integral with a sliding sleeve 4, suitably consists of a softrubber, while the insulating body 1 consists of a hard insulatingmaterial e. g. synthetic material. The sleeve 4 carrying the protectioncap is slidably guided on the insulating body 1 and on the cable 5,emerging from the latter. Therefore the protection cap 3 extending atright angles from one of the longitudinal sides of the insulating body,can be displaced from its position of use (Fig. 1), in which it isplaced in the range of the face side of the plug body 1 carrying thepins 2, into its out-of-use position (Fig. 2) at the lower end of theinsulating body 1, where obviously it will not hinder in inserting theplug also into a countersunk socket.

2,729,797 Patented Jan. 3, 1956 The plug shown in Figs. 3-5 is oneserving for connection to connecting sockets having bayonet armatures asthey are usual in different countries, e. g. Australia. Also here, theplug body 6a, 6b and the protection cap 7 with its support 8 are formedas separate parts. The plug body, for instance consisting ofelectrically properly insulating, hard synthetic material comprises acylindrical head portion 6a, having at its face side the two contacts 9and at its circumference two bayonet engaging pins 14, and a flat shaftportion 6b. In the latter the terminals 10 are provided, in which thestrands of the current supply cable are held by means of screws 12. Theshaft portion 6b and the cable end emerging from the latter are enclosedby a cover 13 of insulating material. With its shaft portion 6b enclosedby the cover 13, the plug body is inserted in a corresponding opening 15of the protection cap-support 8 in the position of use of the protectioncap 7, in which the latter according to Fig. 3 protects the cutter headof an electrical dry-shaver. This support 8 can be slid back from theshaft portion 6b of the plug body onto the cable 11 together with theprotection cap 7. As shown in Fig. 4, the protection cap 7 can no moreobstruct the insertion of the contact carrier 6a into the connectingsocket in this position. Thereby the cover 13 prevents the user fromgetting into contact with the current carrying parts of the shaft 6b.

By means of the described arrangement plugs are provided, the contactcarriers of which, taking up relatively little space when the plug isnot in use, form a compact unit with the protection cap, while thelatter, when using the plug, can he slid back to such an extent over thecable that the plug may be properly applied.

It should of course be understood that modifications may be made in theillustrated and described embodiments without departing from theinvention as set forth in the accompanying claims.

We claim:

1. A plug for electrical apparatus comprising an insulating body, plugcontacts at one end of said insulating body, a protection cap forsensitive apparatus parts and a cap support slidably arranged on saidinsulating body, said protection cap and said insulating body beingformed as separate parts, said cap support having a recess, saidprotection cap and its support being movable from one position in whichthe insulating plug body is nested within said recess in said capsupport and said cap is arranged adjacent the contact carrying portionof said body to a second position away from said contact carryingportion of said insulating body.

2. A plug according to claim 1, wherein said insulating body is providedwith plug pins for insertion in corresponding bushings of a socket andsaid support of the protection cap having sleevelike configuration isslidable on the insulating body such that the protection cap extendingat right angles from said support, in its position of use is arranged inthe range of the face side of the insulating body carrying the plugpins.

3. A plug according to claim 1, wherein the insulating body is providedwith a cylindrical contact-carrier having bayonet engaging pins forinsertion into a bayonetsocket and with a shaft portion, said shaftportion and the cable end emerging from the latter being enclosed by acover of insulating material, on which the support of the protection capis slidably arranged.

Kolbert et al. May 30, 1944 Wilson Aug. 21, 1945

